The objective of this study is to determine the risks of macrosomia, LGA, and Caesarean section associated with a diagnosis of pre-gestational diabetes or gestational weight gain.

This is a retrospective cohort study utilizing data from the Perinatal Surveillance Database of Newfoundland & Labrador from 2001 – 2020. Multivariate logistic regression analyses were used to determine odds ratios (OR) associated with GWG and pre-gestational diabetes for the outcomes macrosomia, LGA, and CS, while controlling for other known risk factors.

There were 234 pregnancies complicated by pre-gestational diabetes and 22,048 without diabetes included. There was no significant difference in absolute GWG between groups (15.2 kg vs. 15.5 kg, p = 0.12), however more women with pre-gestational diabetes had excessive GWG (85.1% vs. 78.5%, p = 0.04). Pre-gestational diabetes was a significant predictor of LGA (OR 5.21, 95% CI 3.96 – 6.87), macrosomia (OR 2.63 95% CI 1.98 – 3.48), and Caesarean section (OR 3.44, 95% CI 2.60 – 4.56). The OR associated with excessive GWG were lower for these same outcomes (LGA OR 2.73, 95% CI 2.40 – 3.11; macrosomia 2.38, 95% CI 2.12 – 2.69; Caesarean section OR 1.29, 95% CI 1.19 – 1.39).

We have identified that pre-gestational diabetes is the most significant risk factor for poor outcomes such as LGA, macrosomia, and Caesarean section, although excessive GWG also plays a role.